The present invention relates to a precision screwdriver in which a switch is received in a rotary cover at the end of the grip for controlling the on/off of a bulb in the grip so as to provide an illumination for the work.
FIGS. 7 and 8 show an existing screwdriver having a grip 90 in which a light emitting device 91 is installed. A rear end of the light emitting device 91 is disposed with a switch 92 and a rear end of the grip 90 is disposed with a cap member 93 having a central resilient button 94. By means of depressing the resilient button 94, the switch of the light emitting device 91 can be switched on or off. The front end of the grip 90 is fixed with a transparent casing 95 by an outer cover 97. The front end of the casing 95 is disposed with a stem 96 equipped with a tool head 98. The light emitting device 91 serves to provide an illumination for working.
In use of a precision screwdriver, the end face of the rear end of the grip must be pushed by the user's fingers or palm so as to facilitate use of the precision screwdriver. Therefore, in the case that the above structure is applied to the precision screwdriver, the user may unintentionally touch the resilient button 94 and the cap member 93 cannot be rotated. This leads to inconvenience in use.
In addition, the transparent casing 95 is fixed with the grip 90 by the fastening force of the outer cover 97 and the grip 90. Therefore, when the user rotates the grip 90 with a greater torque, the transparent casing 95 will slide relative to the grip 90 and thus the application force exerted onto the grip 90 can be hardly accurately transmitted to the tool head 98 of the stem 96 for rotating a work piece.